U.S. patent number 4,814,894 [Application Number 06/720,608] was granted by the patent office on 1989-03-21 for image transmitting system having density selection.
This patent grant is currently assigned to Canon Kabushiki Kaisha. Invention is credited to Takehiro Yoshida.
United States Patent |
4,814,894 |
Yoshida |
March 21, 1989 |
**Please see images for:
( Certificate of Correction ) ** |
Image transmitting system having density selection
Abstract
An image transmitting method in an image transmitting apparatus
such as a facsimile apparatus having a plurality of transmission
modes in which pixel densities differ. This method comprises the
steps of: detecting a size of a recording paper on the reception
side; detecting a size of an original to be transmitted;
automatically selecting the transmission mode of a high pixel
density in the case where the size of the transmitting original is
larger than the size of the recording paper; transmitting the image
of the transmitting original to the reception side; and detecting
the receivable mode on the reception side. With this method, even
in case of reproducing the image in the reduction size mode on the
reception side, the image with a high image quality can be always
derived irrespective of the selection of the image quality mode of
the operator.
Inventors: |
Yoshida; Takehiro (Tokyo,
JP) |
Assignee: |
Canon Kabushiki Kaisha (Tokyo,
JP)
|
Family
ID: |
13567107 |
Appl.
No.: |
06/720,608 |
Filed: |
April 8, 1985 |
Foreign Application Priority Data
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Apr 16, 1984 [JP] |
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59-75123 |
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Current U.S.
Class: |
358/426.02;
358/449; 358/451 |
Current CPC
Class: |
H04N
1/33315 (20130101) |
Current International
Class: |
H04N
1/333 (20060101); H04N 001/387 () |
Field of
Search: |
;358/298,287,293
;355/14SH,14C |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Hartary; Joseph W.
Attorney, Agent or Firm: Fitzpatrick, Cella, Harper &
Scinto
Claims
What is claimed is:
1. An image transmission apparatus having a plurality of
transmission modes, a pixel density of each mode differing from
that of others of the modes, and the modes including a high pixel
density mode and a low pixel density mode, said apparatus
comprising:
indication means for manually indicating one of the transmission
modes;
first detection means for detecting a size of a recording sheet at
a reception side on the basis of a control signal from the
reception side;
second detection means for detecting a size of an original
document;
mode selection means for selecting the transmission mode in
accordance with the indication of said indication means, except
that said mode selection mode selects a transmission mode of high
pixel density irrespective of the indication of said indication
means when the document is larger than the size of the recording
sheet;
transmission means for transmitting an image signal representing an
image of the original document in the transmission mode selected by
said mode selection means; and
third detection means for detecting a mode on the reception side in
which the reception side is able to receive, in response to a
control signal from the reception side,
wherein said mode selection means selects the transmission mode of
high pixel density responsive to said third detection means
detecting that the reception side can receive a transmission in the
transmission mode of high pixel density and the size of the
original document is larger than that of the recording sheet.
2. An image transmitting method in a transmitting appartus having a
plurality of transmission modes in which pixel densities differ,
comprising the steps of:
detecting a size of a recording paper on the reception side;
detecting a size of an original to be tranmitted;
detecting the receivable mode on said reception side;
automatically selecting the transmission mode of a high pixel
density in the case where the size of said transmitting original is
larger than the size of said recording paper; and
transmitting an image of said transmitting original to the
reception side,
wherein, in said selecting step, the transmission mode of a high
pixel density is automatically selected in cases in which the
reception side can receive the transmission mode of a high pixel
density and also where the size of the transmitting original is
larger than the size of the recording paper.
3. An image transmitting method in a transmitting apparatus having
a plurality of transmission modes, a pixel density of each mode
differing from that of others of the modes, and the modes including
a high pixel density mode and a low pixel density mode, said method
comprising the steps of:
indicating one of the transmission modes;
detecting a size of a recording sheet on the reception side on the
basis of a control signal from the reception side;
detecting a size of an original document;
detecting a mode on the reception side in which the reception side
is able to receive, in response to a control signal from the
reception side;
selecting the transmission mode in accordance with the mode
indication, except that a transmission mode of high pixel density
is selected irrespective of the mode indication when the document
is larger than the size of the recording sheet; and
transmitting an image signal representing an image of the original
document in the selected transmission mode, wherein the image
signal is transmitted when the size of the orginal document is
larger than that of the recording sheet,
wherein, in said selecting step, the transmission mode of high
pixel density is selected responsive to detection that the
reception side can receive a transmission in the transmission mode
of high pixel density and the size of the original document is
larger than that of the recording sheet.
Description
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an image transmitting method for
transmitting an image and, more particularly, to an image
transmitting method for transmitting an image in a plurality of
image quality modes.
2. Description of the Prior Art
Recently, there are many facsimile apparatuses which are
constituted such that communication can be performed in a plurality
of image quality modes, including at least a standard mode and a
high image quality mode in which an image density is higher than
that in the standard mode. In the conventional apparatus, a proper
image quality can be selected from those image quality modes in
accordance with an original such as a drawing, document or the
like.
In general, a mode selection switch is provided on an operation
panel or the like and the operator operates this switch to select
the image quality mode. Hitherto, when the standard mode has been
selected by an apparatus on the image transmission side, the image
is transmitted in the standard mode irrespective of the size of the
original and the density of the image information. Therefore, in
this case, if the size of the recording paper in an apparatus on
the reception side is smaller than the original size on the
transmission side, the image is reduced upon transmission, so that
there is a drawback that an original on which fine characters are
written or the like is reproduced in a size which is very difficult
to read.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide an image
transmitting method in which the foregoing drawback is
eliminated.
It is another object of the invention to provide an image
transmitting method in which an image of a high image quality can
be derived even in the case of reproduction on the reception side
on the reduction size mode.
According to the present invention, these objects are obtained by
provision of an image transmission system including an apparatus
having a plurality of transmission modes, including at least a high
pixel density mode and a low pixel density mode, first and second
means respectively for detecting size of a recording sheet at a
reception side on the basis of a control signal from the latter and
the size of an original document, and mode selection means for
selecting the transmission mode in accordance with an indication of
mode provided by an indication means, which may be operable by an
operator. The mode selection means, however, automatically selects
the high pixel density transmission mode irrespective of the
indication provided by the indication means, when the detected size
of the original document is larger than that of the recording
sheet. A third detection means may also be provided for detecting
when the reception side is able to receive a high pixel density
transmission mode.
Other objects and features of the present invention will be more
fully appreciated from the following detailed description with
reference to the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a block diagram showing an arrangement of the main part
of a facsimile apparatus in which the present invention is
employed; and
FIG. 2 is a flowchart for explaining a control procedure in the
arrangement of FIG. 1.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
The present invention will now be described in detail hereinbelow
with respect to an embodiment shown in the drawing, in which a G3
facsimile apparatus complying with the CCITT Recommendation T4 will
be explained hereinbelow as an exemplary embodiment.
FIG. 1 shows an arrangement of the main part of the facsimile
apparatus in which the present invention is employed. In FIG. 1, a
communication line 2a such as a telephone line or the like is
connected to an NCU (network control unit) 2. The NCU 2 performs
the connection control of a switched network, holding of a loop,
switching operation from a communication apparatus such as an
ordinary telephone set, etc., to a data transmission path, or the
like.
A hybrid circuit 4 is connected through a signal line 2b 1to the
post or output stage of the NCU 2. The hybrid circuit 4 serves to
separate a transmission signal and a reception signal. The
reception signal is supplied through a signal line 4a to a V21
demodulator 6, while the transmission signal is inputted from a DCS
signal sender 14 through a signal line 14a to the hybrid circuit
4.
The V21 demodulator 6 is connected to the signal line 4a, and
performs the demodulating operation complying with the CCITT
Recommendation V21, and the result of demodulation is inputted
through a signal line 6a to a DIS signal detector 8.
The DIS signal detector 8 detects a DIS (digital identification)
signal transmitted from the image reception side from the
demodulated signal. When the DIS signal is detected, the detector 8
generates a pulse onto a signal line 8a and at the same time
outputs the information of the 15th, 17th and 18th bits in the FIF
(facsimile information field) of this DIS signal to a control
circuit 16 through signal lines 8a, 8c and 8d, respectively.
The control circuit 16 consists of a microprocessor and a memory
and the like and performs the control for a recording section,
image reading section and the like (not shown) and the control for
the overall communicating operation. In this invention, an original
size detector 10 and an image quality mode detector 12 for the
control which will be explained later are connected to the control
circuit 16.
The original size detector 10 detects the size of the original in
the original reading section (not shown) using a detecting device
such as a photointerrupter or the like and communicates the size of
the original to the control circuit 16 through signal lines 10a and
10b. When the original installed is the A4 size, which is the
standard size based on the G3 standard, "0" and "0" are outputted
onto the signal lines 10a and 10b, respectively. In the case of an
original of the B4 size, "1" and "0" are outputted onto the signal
lines 10a and 10b, respectively. In the case of the original of the
A3 size, "0" and "1" are outputted onto the signal lines 10a and
10b, respectively.
The image quality mode detector 12 checks the state of the image
quality selection switch provided on the operation panel or the
like, thereby detecting the mode selected by the operator. If the
standard mode is selected, "0" is outputted and if the high image
quality mode is selected, "1" is outputed to the control circuit 16
through a signal line 12a.
The DCS signal sender 14 is shown as the circuit of the
transmission system. An arrangement of the transmission system of
the image signal may be similar to that of the prior art and is not
shown here.
When a pulse is generated onto the signal line 16a from the control
circuit 16, the DCS signal sender 14 outputs a DCS (digital
command) signal to the hybrid circuit 4 through the signal line
14a. In this case, the value inputted through a signal line 16b
from the control circuit 16 has been set into the 15th bit in the
FIF of the DCS signal.
Subsequently, the image transmitting operation in the foregoing
arrangement will be explained with reference to a flowchart in FIG.
2. FIG. 2 shows a part of the control procedure in the phase B
(preparation for transmission) of the control circuit 16. There
will be described hereinbelow the case where the size of the
recording paper on the reception side is either A3, A4 or B4 and
the original size is also one of those sizes.
In the image transmitting operation, the control circuit 16 first
waits for the generation of a pulse onto the signal line 8a in step
S20 in FIG. 2. That is, a check is made to see if the DIS signal
has been transmitted or not from the image reception side.
In the case where the DIS signal is transmitted, a check is made in
step S22 to see if the signal line 8b is "1" or not, i.e., if the
15th bit in the FIF of the relevant DIS signal is "1" or not, that
is to say, if the apparatus on the distant side can record in the
high image quality mode or not. If the distant side does not have
the high image quality recording mode, the processing routine
advances to step S40 and the image transmission is executed
similarly to the prior art.
In the case where the distant side has the high image quality mode,
a check is made in step S24 to see if the signal line 10a is "0" or
not, i.e., if the size of the original is B4 or not. When the
original size is B4, step S30 follows. In other cases than B4, step
S26 follows.
In step S26, a check is made to see if the signal line 10b is "0"
or not, that is, if the original size is A3 or not. If the answers
are all YES in steps S24 and S26, the original size is determined
to be A4, so that the processing routine advances to the foregoing
step S40. In case of the original of A3 size, step S28 follows.
In step S28, a check is made to see if the signal line 8d is "0" or
not, i.e., if the size of the recording paper on the reception size
is A3 or not (thus, whether it is A4 or B4). In the case of the
recording paper of A3 size, step S40 follows. In the case where the
recording paper is A4 or B4, step S34 follows.
On the other hand, a check is made in step S30 to see if the signal
line 8c is "0" or not, that is, whether the recording paper on the
reception side is B4 or not is detected. In the case of the
recording paper of B4 size, step S40 follows. In other cases than
B4, step S32 follows.
In step S32, a check is made to see if the signal line 8d, is "0"
or not, and thus to see if the recording paper is A3 size or not.
In the case of the recording paper of A3 size, step S40 follows.
When both answers in steps S30 and S32 are YES, the size of the
recording paper is determined to be A4 and then the processing
routine advances to step S34 in this case.
Therefore, in the case where the reception side has the high image
quality mode, when the original size is B4 and the recording paper
size is A4 or when the original size is A3 and the recording paper
size is A4 or B4 which is smaller than A3, the processing routine
advances to step S34.
In the foregoing case, the image is reduced and reproduced;
therefore, the high image quality mode is forcedly selected
irrespective of the selection of the operator. Practically
speaking, the control circuit 16 outputs "1" onto the signal line
16b in step S34 and sets the information representing that the
transmission is performed in the high image quality mode into the
FIF of the DCS signal. Thereafter, in step S36, a pulse is
generated onto the signal line 16a and the DCS signal is
transmitted through the hybrid circuit 4 and NCU 2.
In step S38, the transmission is performed in the high image
quality mode in accordance with a procedure similar to the prior
art. In this case, the image data is reduced as necessary in
keeping with the original size.
On the other hand, when the original size is B4 and the recording
paper size is B4 or A3, or when the original size is A4 and the
recording paper size is A3, or the like, that is, in the case where
there is no need to reduce the image since the size of the
recording paper is larger than the original size, the processing
routine advances to step S40. Thus, the communication is carried
out in the image quality mode according to the selection of the
operator which was detected by the image quality mode detector 12.
However, since the reception side has merely the standard mode in
the case where the processing routine is jumped from step S22, even
if the operator selects the high image quality mode, the standard
mode would be selected; this situation is similar to the prior
art.
As described above, the high image quality mode having a high pixel
density is forcedly selected only in the case where the image is
reduced and transmitted. Consequently, even if the communication is
performed while the standard mode was selected by the operator on
the transmission side, the original image with a suitable
resolution and image quality can be reproduced on the reception
side. The present invention is effective particularly in the case
where there is a large difference in size between the original and
the recording paper. The above-described arrangement can be
implemented due to slight changes in software and hardware and it
is remarkably simple and cheap.
Although the case where there are two kinds of image quality modes
has been described in the above, the fundamental concept of the
control is also the same if there are a greater number of image
quality modes. In addition, the embodiment regarding the G3
facsimile apparatus has been shown in the above, but the invention
can be obviously similarly implemented even in other communication
modes such as the G2 mode, G4 mode, etc.
As will be apparent from the above description, according to the
present invention, there is adopted such an arrangement that: the
size of the recording paper on the reception side is detected; the
size of the original installed is detected; and the image is
forcedly transmitted in the high image quality mode in the case
where it is determined that the original size is larger than the
recording paper size due to the above-mentioned detections of the
sizes of the recording paper and of the original. Therefore, it is
possible to simply and cheaply provide an exceelent image
transmitting method which can always reproduce the image with a
proper resolution and a good image quality on the reception side
irrespective of the selection of the image quality mode of the
operator.
The present invention is not limited to the foregoing embodiment
but many modifications and variations are possible within the
spirit and scope of the appended claims of the invention.
* * * * *